Diagnosing disorders and afflictions in the human brain with non-invasive procedures is important medically and scientifically.
This invention relates to determining the nature of brain conditions using quantitative electrophysiology. In particular, the invention relates to analyzing electroencephalographic information in a manner to permit assessment of the nature of brain conditions. The invention is further directed to give a characterization of afflictions such as dementia, being selective for multi-infarct dementia or Alzheimer's disease.
Information which is obtainable from an EEG includes conventional EEG data representative of electrical activity in different brain regions. When these data are digitized and processed as in quantitative EEG ("qEEG"), it is possible to obtain topographical brain mapping of electrical activity in different brain regions. From a qEEG unit, it is also possible to obtain measurements of absolute power, relative power, and evoked potentials. Quantitative EEG techniques represent an advance over traditional EEG methods because they permit the detection of trends which are difficult or impossible to discern by direct visual inspection of the EEG voltage tracings.
A shortfall of all these EEG and qEEG data is often the inability to provide convincing information regarding brain physiologic differences between normal and abnormal conditions, and to distinguish between the nature of different abnormal conditions.
Prior investigations of quantitative electroencephalography (qEEG) have detected several parameters that are useful in distinguishing elderly subjects with dementia from control subjects. They also are useful in determining the likelihood that a degenerative brain disease, such as Alzheimer's disease (DAT) that affects primarily the cerebral cortex, or a disease prominently affecting subcortical white matter, such as multi-infarct dementia (MID), are contributing to cognitive losses in an individual case. Most of these parameters, however, are of limited usefulness for the diagnosis of dementia, accurately classifying a majority of subjects only when clear impairment is present, rendering the parameter's information merely confirmatory.